Recently, a large number of information processing devices having the function of a graphic functional card exist. In addition, display signals for performing screen display on a monitor or the like of such an information processing device have been digitalized. The information processing device configured to output a digital display signal includes, for example, a port compliant with a display port (DP). Through the display signal digitalization, a signal compatible with a video graphic array (VGA) interface has become less likely to be directly output from a graphic chip which is set for graphics output. The VGA interface is also called an analog RGB (red, green, and blue) interface.
However, the use frequency of an analog VGA input display by a user of the information processing device remains high. To handle such a situation, it is typical to mount, on the information processing device, a DP-to-VGA conversion chip as an integrated circuit (IC) configured to perform protocol conversion from a signal compliant with a display port to a signal compliant with analog VGA. Accordingly, the information processing device can be connected with a display including the VGA interface by using a cable through which an RGB signal is transmitted and received without using a table with which a signal compliant with a display port is converted into an RGB signal.
The DP-to-VGA conversion chip has firmware. It is preferable to update the firmware of the DP-to-VGA conversion chip at manufacturing of the information processing device on which the DP-to-VGA conversion chip is mounted or in case of trouble of the DP-to-VGA conversion chip. The firmware of the DP-to-VGA conversion chip is updated by using a tool provided by the manufacturer of the DP-to-VGA conversion chip. Many of such tools update the firmware through an application programming interface (API) compatible with an operating system (OS) application. Thus, the firmware update is often affected by restriction due to the API.
When the firmware is updated through the API, a device ID (Identifier) as a double (D) WORD identifier is specified to specify a port as the target of the firmware update. The graphic chip acquires the device ID through another API. When a display is connected in advance before the device ID is acquired through the API, a unique DWORD identifier indicating the display is returned to the graphic chip. Thus, the display needs to be connected when a firmware update API is used.
The following specifically describes the process of firmware update. The graphic chip receives an instruction to update the firmware of the DP-to-VGA conversion chip from a central processing unit (CPU). Subsequently, the graphic chip executes EnumAttachableDevices Method as a command for determining a port connected with a display. When a display is connected, the graphic chip acquires a value indicated by a DWORD pointer as a unique identifier. Thereafter, the graphic chip inputs the acquired identifier as a device ID, and in addition, inputs data of a firmware for update. Thereafter, the graphic chip updates the firmware of the DP-to-VGA conversion chip by using the device ID and the firmware for update.
In a technology of converting a digital signal of display data into an analog signal, a plurality of gradation voltages provided with gamma correction are generated, and one of the gradation voltages is selected and provided with D/A conversion. In a conventional technology of software update, connection is automatically established with a server storing update data, and update is automatically performed.
Examples of conventional techniques are Japanese Laid-open Patent Publication No. 2015-109114 and Japanese Laid-open Patent Publication No. 2005-242294.
However, connecting a display to an information processing device needs work and is cumbersome when updating the firmware of a DP-to-VGA conversion chip.
In the conventional technology in which conversion to an analog signal is performed by using gradation voltages provided with gamma correction, chip firmware update is not considered, and thus it is difficult to reduce work at update. In the conventional technology in which connection is automatically established with a server to perform update, a display is connected when updating the firmware of a DP-to-VGA conversion chip, and thus it is difficult to reduce work at the time of the update.